OK, we’re going to draw the dot structure
for Chlorine gas–a poisonous green gas. This is Dr. B. And we’ll start out by figuring
out how many valence electrons we have for Chlorine. On the periodic table, it’s in group
7 or 17, so it has 7 valence electrons; but we have two of them, so let’s multiply that
times two for a total of 14 valence electrons. So we’re going to spread those around the
atoms, fill the octets, form a chemical bond. So here’s Chlorine, and another Chlorine.
Let’s start by putting two valence electrons between the Chlorines. That forms the chemical
bond. And then we’re going to spread them around the outside atoms, trying to give each
one eight. So we have 2, 4, 6, 8, 10, 12, 14. We used all 14 up. Now let’s see if we
have octets, eight valence electrons around each. That Chlorine has 8, and this Chlorine
right here, 2, 4, 6, has 8 as well. So we’ve actually finished this Lewis structure for
Cl2; a pretty straightforward one. And let’s just count: 2, 4, 6, 8, 10, 12, 14. So we’re
good there. We could also draw it as a structural formula that would look like this. These two
electrons right here would be represented by a single line that shows you a pair of
valence electrons, and it shows that they’re bonded. That’s the Lewis structure for Cl2,
Chlorine gas. This is Dr. B., and thanks for watching.